<div class="btn-group" data-toggle="buttons">
    
    <label class="btn btn-default btn-sm">
        <select name="" id="">
        <option value=>部门</option>
        <option value="">21</option>
        <option value="">21</option>
        <option value="">21</option>
        <option value="">21</option>
        </select>
    </label>
   
</div>